The RamSan OS now allows 512-byte and 4KB block access for better support of mixed workloads

Texas Memory Systems (TMS) today announced an upgrade to its RamSan operating system that's designed to support high-speed access to large and small block data sets.

The company also announced its next-generation multi-level cell NAND flash storage array, the RamSan 820, which offers enterprise-class hardware redundancy and 40Gbps InfiniBand connectivity.

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The predecessor to the RamSan-820 -- the RamSan-720 flash array, which has an identical architecture

The RamSan-820 comes with either 12TB or 24TB of usable capacity without system-level RAID, or 10TB or 20TB of usable capacity with RAID, which is exactly double the capacity of its predecessor, the RamSan-720.

The biggest difference between the RamSan-720 and the new RamSan-820 is the NAND flash being used. The RamSan-720 uses more-expensive, less-dense single-level cell (SLC) NAND, while the 820 uses enterprise-class multi-level cell (eMLC) NAND.

"You get the density of MLC but closer to the reliability of SLC flash," said Erik Eyberg, a senior analyst at TMS.

And TMS is selling the new system at a far lower price. The RamSan-720 was priced at $25 per usable gigabyte of capacity; the RamSan-820 is half that price, at $12.50 per usable gigabyte.

In a typical consumer drive, which uses MLC flash, the number of program-erase cycles (which determine a drive's life span) varies from 3,000 to 5,000, while an eMLC drive can endure an average of 30,000 P/E cycles, or roughly 10 times more than consumer MLC systems. In comparison, a top-tier SLC-based SSD can endure up to 100,000 P/E cycles.

TMS's previous eMLC array, the RamSan-810, has the same performance as the 820, but it wasn't built with a fully redundant architecture and therefore isn't designed for enterprise-class use.

On the performance front, the RamSan-820 offers up to 400,000 sequential I/Os per second (IOPS), or 4GBps throughput.

Like the RamSan-720, the 820 is also fully redundant for enterprise-class data center use. The 1U (1.75-in. high) box has redundant management controllers, interfaces, cross-bar switches, data buses, RAID controllers, power supplies, power paths, clock circuits and batteries. The flash cards are also dual-ported for redundancy.

TMS also announced a firmware upgrade to its RamSan operating system (which resides in the flash controller) that allows 512-byte, sub-page access to data. The previous iteration of the operating system was tuned for 4KB or 8KB page access, meaning large block access.

"We had not as great small-block support," Eyberg said. "Now the firmware upgrade allows for great 512-byte support and 4KB support. So our box is even better for mixed workloads."

While most file systems hold to a single block access size, some large-scale, clustered file systems have access patterns that vary between 512-byte and 64KB block sizes.

"By introducing this support, we have extreme performance on any block size," Eyberg added.